# How to generate a random boolean using JavaScript ?

The task is to generate random boolean value. Here we are going to use JavaScript to achieve the goal.

Approach 1:

• Calculate Math.random() function.
• If it is less than 0.5, then true otherwise false.

Example 1: This example implements the above approach.

 `  ` `<``html``>  ` ` `  `<``head``>  ` `    ``<``title``>  ` `        ``How to generate a random  ` `        ``boolean using JavaScript? ` `    `` ` `  ` ` `  `<``body` `style` `= ``"text-align:center;"` `id` `= ``"body"``>  ` `     `  `    ``<``h1` `id` `= ``"h1"` `style` `= ``"color:green;"` `>  ` `        ``GeeksForGeeks  ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_UP"` `style` `=  ` `        ``"font-size: 15px; font-weight: bold;"``> ` `    `` ` `     `  `    ``<``button` `onclick` `= ``"gfg_Run()"``>  ` `        ``Click here ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_DOWN"` `style` `=  ` `        ``"font-size: 23px; font-weight: bold; color: green; "``> ` `    `` ` `     `  `    ``<``script``> ` `        ``var el_up = document.getElementById("GFG_UP"); ` `        ``var el_down = document.getElementById("GFG_DOWN"); ` `         `  `        ``el_up.innerHTML = "Click on the button to " ` `                        ``+ "generate random boolean."; ` `         `  `        ``function gfg_Run() { ` `            ``el_down.innerHTML = Math.random() >= 0.5; ` `        ``}          ` `    ``  ` `  ` ` `  ` `

Output:

• Before clicking on the button:
• After clicking on the button:

Approach 2:

• Create an array containing ‘true’ and ‘false’ values.
• Calculate Math.random() and round its value.
• Use rounded value as the index to the array, to get boolean.

Example 2: This example implements the above approach.

 `   ` `<``html``>   ` ` `  `<``head``>  ` `    ``<``title``>  ` `        ``How to generate a random ` `        ``boolean using JavaScript? ` `    `` ` `  ` ` `  `<``body` `style` `= ``"text-align:center;"` `id` `= ``"body"``>   ` `     `  `    ``<``h1` `id` `= ``"h1"` `style` `= ``"color:green;"` `>   ` `        ``GeeksForGeeks   ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_UP"` `style` `=  ` `            ``"font-size: 15px; font-weight: bold;"``> ` `    `` ` `     `  `    ``<``button` `onclick` `= ``"gfg_Run()"``>  ` `        ``Click here ` `    `` ` `     `  `    ``<``p` `id` `= ``"GFG_DOWN"` `style` `=  ` `        ``"font-size: 23px; font-weight: bold; color: green; "``> ` `    `` ` `     `  `    ``<``script``> ` `        ``var el_up = document.getElementById("GFG_UP"); ` `        ``var el_down = document.getElementById("GFG_DOWN"); ` `        ``var ar = [true, false]; ` `         `  `        ``el_up.innerHTML = "Click on the button to " ` `                        ``+ "generate random boolean."; ` `     `  `        ``function gfg_Run() { ` `            ``var index = Math.round(Math.random()); ` `            ``el_down.innerHTML = ar[index]; ` `        ``}          ` `    ``  ` `   ` ` `  ` `

Output:

• Before clicking on the button:
• After clicking on the button:

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